DE10019888B4 - Transparent electronic component arrangement and method for its production - Google Patents

Abstract

Carrier substrate comprises a conducting layer transparent or quasi-transparent in the visible wavelength region applied to a transparent substrate (1). An independent claim is also included for a process for the production of an electronic component with the carrier substrate. Preferred Features: The conducting layer is a metal oxide selected from InO x: Sn, SnO x: F, SnO x: Sb, ZnO x: Ga, ZnO x: B, ZnO x: F, ZnO x: Al or Ag/TiO x. The conducting layer is applied by CVD, PVD, spray pyrolysis, sputtering or by using a sol-gel process. The conducting layer may be made from a metal, preferably Al, Ag, Au, Ni or Cr. The substrate is made from glass or plastic.

Description

The invention relates to an electronic component arrangement which is transparent in the visible wavelength range and comprises a transparent substrate and a conductive layer applied to the transparent substrate, the conductive layer being transparent or virtually transparent. Furthermore, the invention relates to a method for producing such an electronic component arrangement. The electronic component arrangement comprises, in particular, lighting means, preferably light-emitting diodes.

Light-emitting diodes, so-called LEDs, are suitable for a large number of applications in lighting technology. So-called LED modules comprise a multiplicity of light-emitting diodes on a carrier substrate. The light-emitting diodes arranged on the carrier substrate in turn form a display unit which DE 197 29 469 A1 For example, it can be used to display destinations in a bus. Such a display matrix is from the DE 197 29 469 A1 known. In the display device according to the DE 197 29 469 A1 the light-emitting diodes are arranged on a transparent film, wherein the film comprises conductor tracks for the power supply of the light sources. According to the DE 197 29 469 A1 For example, the traces for powering the LED diodes are made by a conductive paste or liquid that is opaque and printed or attached to transparent foil.

Preferably, the conductor tracks according to the DE 197 29 469 A1 arranged in matrix form.

The contacting of the individual LEDs on the tracks is made with conductive adhesive.

A disadvantage of the display device according to the DE 197 29 469 A1 is that the trace applied on the transparent substrate is opaque. Another disadvantage is the expensive application to the transparent substrate, for example by attaching or printing.

From the EP 0 900 971 A1 is a lighting device with light emitting diodes has become known, which consists of a plurality of mounted on the surface of a glass plate light emitting diodes. The LEDs are electrically connected to the glass plate mounted, designed as a thin and invisible layer interconnects. The tracks and their connections are mounted on the same surface of the glass plate on which the LEDs are located.

According to the EP 0 900 971 A1 the printed conductors are applied by vaporization of metal on the glass plate, whereby a corresponding masking is used before the vapor deposition.

A disadvantage of the lighting device according to the EP 0 900 971 A1 is that the tracks are already structured during the vapor deposition process.

From the JP 04199754 A (Abstract) discloses a method of manufacturing an LED display device in which an ITO film is applied to a glass substrate. On the ITO film, a metal layer, such as Au, applied and then placed on this metal layer, the light source.

From the US 4,959,510 A For example, a printed circuit with a glass substrate has been disclosed which comprises ITO or SnO ₂ lines as signal lines. For example, light-emitting diodes can be arranged on the printed circuit.

The DE 198 54 899 C1 shows a lighting unit, in which on a transparent support plate with an electrically conductive structure, in particular a structured ITO layer, lighting means, in particular light emitting diodes, are mounted. The bulbs in the DE 198 54 899 C1 are unprotected and emit their light through the carrier plate.

From the US 5,469,020 A For example, the inclusion of an active light emitting component between two electrodes, which are preferably made of plastic, is shown. The bulbs are hereby spherical light-emitting diodes, which are enclosed in a film.

From the JP 07-076131 A (Abstract) has become known an arrangement in which lighting means, in particular an LED array, is connected to a first substrate of high strength and low thermal expansion and a second transparent substrate is arranged above the lighting means to the bulbs against the action of compressive forces protect.

The US 5,825,442 A shows a liquid crystal display comprising a first and a second transparent electrode layer, between which a liquid crystal layer is enclosed.

The US 5,706,022 A also shows a display device comprising an optically transparent substrate. Again, the display device relates to a liquid crystal display.

The US 4,952,783 A shows a heater comprising a light-transmissive substrate and a transparent, conductive conductor.

From the EP 0 866 506 A1 For example, a color display device comprising light-emitting diodes arranged in a plurality of rows and columns has become known, the light-emitting diodes being connected between two transparent substrates which serve as electronic circuit boards both from above and from below.

The JP 08-076697 A shows a display device with light-emitting diodes, which in turn are arranged both on a substrate extending above the light emitting diode and a substrate extending below the light emitting diode.

Other disadvantages of some prior art systems were that they did not allow for soldering on transparent traces, and no three-dimensional shaping, as the conductive layers peeled off in forming processes such as bending.

The object of the invention is to provide a component arrangement for electrical or electronic components, in particular for light-emitting diodes or LED modules, comprising a plurality of light emitting diodes, which on the one hand ensures the required transparency, on the other hand is very inexpensive to manufacture and the high production cost of the systems according to avoids the prior art.

According to the invention this object is achieved by a component arrangement according to claim 1 and a method for their preparation according to claim 15.

In the case of the component arrangement according to the invention, the electrical or electronic components, preferably the illuminants, are applied to a transparent carrier substrate and protected by a second transparent substrate. The light sources then lie between the transparent carrier substrate and the further transparent substrate. In this way, the light sources can be additionally protected against environmental influences such as moisture and mechanical shearing.

The conductive layer applied to the transparent substrate is transparent or virtually transparent in the visible wavelength range and can be structured as desired. Metal oxides are preferably used to produce transparent interconnects, for example ITO (InO _x : Sn), FTO (SnO _x : F) or ATO (SnO _x : Sb). Conceivable but are _x and ZnO: Ga, ZnO _x: F, ZnO _x: B, ZnO _x: Al or Ag / TiO _x.

The application of this layer to the transparent substrate is preferably carried out by means of chemical vapor deposition (CVD) or physical vapor deposition (PVD), dip coating, chemical or electrochemical coating.

For example, here are the spray pyrolysis, sputtering or sol-gel process called. The application by spray pyrolysis is particularly cost-effective, ZnO _x : F being preferably used as the coating material. If one wishes to achieve particularly high optical properties, the preferred application method is sputtering.

In contrast to the prior art, systems of any desired three-dimensional shape can be produced with the aid of the aforementioned application methods. For this purpose, the substrate is first brought into the desired three-dimensional shape and then made the application of the conductive layer. This allows, for example, an application in the automotive sector, eg. As the production arbitrarily shaped dashboards or tail lights.

Alternatively, it is also possible that the conductive layer consists of a vapor-deposited or sputtered metal such as Al, Ag, Au, Ni or Cr, which is usually quasitransparent. Metal layers are preferably used at high ambient temperatures.

In the present application, transparent layers or glasses are understood as meaning layers or glasses with a transmission> 90% in the visible wavelength range. In the present application, quasi-transparent layers or glasses are understood as meaning layers or glasses with a transmission of> 60%.

In order to obtain particularly low reflection systems, it is provided in a further development of the invention to apply to the conductive layer a special reflection layer, for example a TiO ₂ , SiO ₂ or a mixed layer of Ti _x Si _1-x O ₂ .

According to the invention, the conductive layer of metal oxide or metal can not only be matrix-shaped as in the prior art, but can be structured as desired. This allows the application of complete structures such as on single-layer PCBs (so-called Printed Circuit Boards). This in turn allows to apply complete electronic circuits to one and the same substrate. The structuring of the conductive layer can be carried out after application by targeted interruption of the layer, for example by means of a laser, which locally heats the coating and evaporates it. When using a laser for introducing the structures into a conductive layer applied over the entire area, it is advantageous if the layer has a particularly high absorption in the region of the laser wavelength of the laser used and the substrate is transmissive for this wavelength. In such a system, virtually all of the energy input into the conductive layer occurs, and the glass surface has little damage. In particular, cracking in the glass surface can be avoided in such a system.

Alternatively, the structuring of a layer applied over the entire area by means of lithography and subsequent etching processes is possible. However, structuring is also conceivable in which already during coating, for example during vapor deposition with the aid of mask techniques, the printed conductors are applied in the predetermined structure.

In order to connect the light-emitting diodes or other electrical components to the carrier substrates, in a preferred embodiment of the invention, connection points, so-called pads, can be applied to the conductive layer. Such connection points comprise a conductive paste or lacquer, for example silver-conducting lacquer or silver-conducting lacquer paste. The application of the individual connection points can be effected by means of screen printing or stencil printing and subsequent baking, wherein such a method can be used in the case of the use of glasses as a transparent substrate at the same time for biasing the glasses. An advantage of such manufactured components is that particularly strong glasses can be obtained without an additional further processing step. Another advantage is that the application of the pads for the first time allows soldering on a transparent substrate. In the prior art, the connection of various components on a substrate in the case of transparent printed conductors has hitherto always been carried out by gluing. Soldering was only possible on opaque tracks. Unlike bonded joints, however, solder joints are more stable, longer-lasting and less sensitive to environmental factors such as humidity, heat, chemicals, etc.

To connect the components or light-emitting diodes to the conductive layer of the carrier substrate via the connection points, the mounting of the carrier substrate with light-emitting diodes can be carried out by known standard methods from the electronics industry, for example by applying solder paste to the individual connection points or connection pads by means of stencil printing. Subsequently, the LEDs are applied to the carrier plate. For this purpose, a chip bonder can be used, which fixes the individual bulbs on the carrier material before the soldering process. After attaching the individual lamps, the carrier substrate is then passed through a reflow oven. Alternatively, the LED's populated with a chip bonder may be passed through a wave solder bath.

Nevertheless, according to the invention, it is also possible to apply a conductive adhesive to the carrier substrate by means of screen printing or stencil printing, so that the lighting means or electrical components can be applied directly to the carrier substrate. Both isotropic conductive and anisotropic conductive adhesive can be used. At very low interconnect spacing, the use of anisotropic adhesive is preferred.

The particular advantage of the present invention is the free structurability. This makes it possible for not only illuminants, for example light-emitting diodes, as in the prior art, to be applied to the carrier substrate, but also other electrical or electronic components. Here, all known electrical and electronic components come into consideration, such as discrete semiconductors, passive and active components, resistors, capacitors, coils, etc.

For example, it is then possible for the entire drive electronics to be applied to the carrier substrate in addition to the light-emitting diodes.

In a particularly preferred embodiment, not only individual electrical or electronic components, such. B. coils or capacitors applied to the carrier substrate, but additional boards or hybrid circuits with independent integrated circuits, which may include, for example, a power source or power control.

In a particularly preferred embodiment, it is provided that the further transparent substrate is likewise provided with a conductive, transparent layer. This makes it possible to contact the light emitting diodes without housing directly between two conductive substrates. Instead of a coating on a transparent substrate may also be provided a conductive plastic film.

The transparent substrate may be both a glass and a plastic substrate. It is particularly preferred if the glass substrate is hardened and prestressed. As particularly preferred glasses lime-soda glasses are used.

In a particularly preferred embodiment, it is provided that a plurality of carrier substrates with lighting means, for. B. light emitting diodes to each other and to contact. This allows carrier substrates of any shape. Also conceivable are three-dimensional objects made of a plurality of carrier substrates, for example a cube or a pyramid of square and triangular base plates.

In addition to the electronic element arrangement, in particular with light sources, such as light-emitting diodes, the invention also provides a method for producing such a component arrangement.

As an application, all those applications are considered in which a lighting, signaling, information presentation or a decorative effect to be achieved. It is particularly preferred to use such component arrangements in furniture and display cabinets, for the representation of logotypes, symbols or graphics, for interior or exterior lighting and for escape route lighting. In a particularly preferred application, such component arrangements, in particular LED modules in the automotive sector are used, for example as a third brake light on the car, which is integrated directly into the rear light. An alternative application in the automotive field involves the use of LED modules directly on the dashboard cover.

The LED modules according to the invention can also be used in so-called composite systems comprising a carrier substrate. For example, a resistive touch panel on which the LEDs are mounted is conceivable.

The invention is explained in more detail by way of example with reference to the drawings. Show it:

1 a not belonging to the invention component.

2a - 2d the typical procedure for producing a carrier substrate with light sources, a so-called LED module.

3 an LED module with applied further electrical component.

4 an LED module with hybrid circuitry applied.

5 two LED modules of different structure.

6 - 7 the connection of LED modules for two-dimensional or three-dimensional geometries.

In 1 , which does not belong to the invention, a carrier substrate with applied conductive layer is shown, which in turn has been structured such that on the transparent carrier substrate 1 a circular track 3 with connecting conductors 5 . 7 is trained. On the circular track 3 are individual connection points 9 arranged. The connection points 9 serve to the individual bulbs, for example, the LEDs 4 conductive to connect to the track and thus ensure the same energy supply. The carrier substrate is preferably a soda-lime glass.

In the 2a to 2d an inventive process sequence for producing a carrier substrate with electrical components, in particular with light emitting diodes is shown. First, the transparent support substrate 1 coated with a conductive layer over the entire surface, for example in the sol-gel process.

Subsequently, according to 2 B a structuring, for example by means of a laser, which locally heats the coating and evaporates produced. The carrier substrates, which are patterned with the aid of a laser, preferably comprise a conductive layer which has a high absorption in the region of the laser wavelength of the laser used and a substrate which is transmissive at this wavelength. In such a system, the glass layer has only minor injuries. In particular, the cracking in such systems can be largely avoided.

The characteristics of the individual regions of the substrate are in 2 B with the reference numbers 11.1 - 11.3 designated. According to the structuring according to 2 B subsequently be in the fields 13.1 - 13.4 individual connection points, so-called connection pads 9 applied. The connection pads 9 comprise a conductive paste or lacquer, for example silver-conductive lacquer or silver paste, and is applied to the conductive substrate by means of screen printing or stencil printing and then baked. By baking, at the same time, pretensioning of the transparent substrate, in particular of the transparent glass substrate, can take place. As a result, a high mechanical strength is achieved in a single process step.

After applying the contacts in the different areas 13.1 - 13.4 these will be as in 2d represents, equipped with a standard method, for example, by solder paste on the connection pads 9 , For example, by means of stencil printing applied. The light-emitting diodes (LEDs) 4 are then applied to the carrier plate, wherein a chip special can be used, the light-emitting diodes 4 attached to the substrate prior to the soldering process. After attaching the individual LEDs, the carrier substrate 1 with the light-emitting diodes mounted on it through a reflow oven or through a wave solder bath.

In one embodiment of the invention, a glass substrate, typically a soda lime glass, is coated with the fluorine doped tin oxide.

The application of the coating takes place as follows:
A soda-lime glass as a transparent substrate is heated to 500 ° C. The glass is then sprayed with monobutyltin chloride and hydrofluoric acid in ethanol, the spray solution having the following composition: monobutyltin chloride 70% ethanol <30% hydrofluoric acid 0.4%

After spraying, the soda-lime glass comprises a transparent, fluorine-doped tin oxide layer.

The description is then separated with a laser. With the help of a doctor blade by Siebdruck a Silberleitplaste, z. As Cerdec SP 1248 applied. The paste Cerdec 1248 is dried in a continuous oven at 140 ° C for 2 min and then baked by a tempering machine at about 700 ° C for a soda-lime glass and pre-stressed. Subsequently, commercially available solder paste is applied by stencil printing and equipped with light-emitting diodes, for example NSCW 100 light-emitting diodes from the company Nichia. In the following reflow soldering, the assembled substrate is preheated to 120 ° C. for 2 minutes and then heated to 235 ° C. for 5 seconds. Then it is slowly cooled.

In 3 an embodiment of the invention is shown in which a transparent carrier substrate 1 on the in different areas 13.1 . 13.2 . 13.3 , Light-emitting diodes 4 with the help of in 2a - 2d was applied described method. In addition to the LEDs 4 The carrier substrate also contains other electronic components, such as resistors 17 , a semiconductor diode 19 as well as a transistor 21 , Instead of individual components, as in 4 shown next to the light emitting diodes 4 Even entire electronic circuits are arranged on the carrier substrate according to the invention. The same components as in the previous figures are also in 4 with the same reference numerals. The electronic circuit, such as the electrical drive or power source is denoted by the reference numeral 23 busy. The versatility of the invention comes from the 5 - 7 out. In 5 Two LED modules of different geometric characteristics are shown, namely a triangular module 100 with three LEDs 102.1 - 102.3 and a rectangular LED module 110 with light-emitting diodes 112.1 - 112.4 ,

The geometrically different LED modules 100 . 110 can like in 6 be connected in a flat configuration to an LED module of any two-dimensional geometric shape as well as to three-dimensional structures as in 7 shown. By shaping the substrate prior to coating with a conductive layer, any three-dimensional structures, for example also curved structures, can be produced.

The invention for the first time specifies a carrier substrate whose conductive layer, in contrast to the prior art, is completely transparent and not opaque. In particular, the method according to the invention allows the glasses to be prestressed simultaneously in a single process step during the firing of the connection point or soldering pads. Due to the free structuring of full-surface coated glasses, it is possible to easily integrate other electronic components on the carrier substrate of the LED modules, such as the control electronics. The structuring can take place independently of the coating with a conductive layer. By the application of connection points, it is possible in a particularly advantageous embodiment of the invention to apply solder joints on a transparent carrier substrate. A further advantage is that any desired geometric shapes can be realized by combining any desired substrate shapes, dyeings and decorative printing.

Claims (21)

Transparent electronic component arrangement, comprising - a carrier substrate for electrical or electronic components, with a transparent substrate ( 1 ) and one on the transparent substrate ( 1 ) conductive layer applied over the entire area, wherein the conductive layer is transparent or quasi transparent and arbitrarily structurable, and wherein the conductive layer is a structuring (laser) produced by a laser ( 11.1 . 11.2 . 11.3 ), - several electrical or electronic components ( 4 . 17 . 19 . 21 ), which are applied to one surface of the carrier substrate and connected to the conductive layer and -a further, transparent substrate, which is arranged over the components applied to the carrier substrate, so that the components are protected between the carrier substrate and the further transparent substrate, wherein - the electronic component array in the visible wavelength range is transparent, the transparent substrate and the further transparent substrate each have a transmission greater than 90% in the visible wavelength range and the conductive layer transparent with a transmission greater than 90% or quasi transparent with a transmission greater than 60% in the visible wavelength range. The transparent electronic component assembly of claim 1, wherein the carrier substrate is characterized in that the conductive layer comprises a metal oxide. Transparent electronic component assembly according to claim 2, characterized in that the metal oxide of one or more of the following metal oxides comprising: - InO _x: Sn - SnO _x: F - SnO _x: Sb - ZnO _x: Ga - ZnO _x: B - ZnO _x: F - ZnO _x : Al - Ag / TiO _x Transparent electronic component arrangement according to Claim 3, characterized in that the conductive layer is applied to the transparent substrate by a sol-gel method using one of the following methods - CVD - PVD - spray pyrolysis - sputtering ( 1 ) is applied. Transparent electronic component arrangement according to one of claims 1 to 2, characterized in that the conductive layer comprises a metal. Transparent electronic component arrangement according to claim 5, characterized in that the metal comprises one or more of the following metals Al, Ag, Au, Ni, Cr. Transparent electronic component arrangement according to one of claims 5 to 6, characterized in that the metal is vapor-deposited or sputtered. Transparent electronic component arrangement according to one of claims 1 to 7, characterized in that the transparent substrate ( 1 ) is a glass or plastic substrate. Transparent electronic component arrangement according to claim 8, characterized in that the glass substrate is hardened and / or biased. Transparent electronic component arrangement according to one of claims 8 to 9, characterized in that the glass or the plastic substrate has any contour. Transparent electronic component arrangement according to one of claims 8 to 10, characterized in that the glass or plastic substrate is printed with decorative printing. Transparent electronic component arrangement according to one of claims 1 to 11, characterized in that the electronic component arrangement has an arbitrary three-dimensional shape. Transparent electronic component arrangement according to one of claims 1 to 12, characterized in that the electronic component arrangement more of the following electrical or electronic components ( 4 . 17 . 19 . 21 ) comprises: - light-emitting diodes - discrete semiconductors - passive and active components - ICs - resistors - capacitors - coils Transparent electronic component arrangement according to one of Claims 1 to 13, characterized in that the electronic component arrangement has an LED module ( 110 ). Method for producing an electronic component arrangement which is transparent in the visible wavelength range, comprising the following steps: a transparent carrier substrate ( 1 ) and another transparent substrate having a respective transmission greater than 90% in the visible wavelength range are provided; - On the transparent substrate, a transparent conductive layer having a transmission greater than 90% or a quasi-transparent conductive layer having a transmission greater than 60% in the visible wavelength range is applied over the entire surface; - After full-surface application, the transparent or quasi-transparent and arbitrarily structurable conductive layer is patterned by means of a laser; On a surface of the carrier substrate are electrical or electronic components ( 4 . 17 . 19 . 21 ) and - connected to the conductive layer after structuring; - The further transparent substrate is disposed over the applied on the transparent substrate components so that - the components are protected between the transparent substrate and the other transparent substrate. A method according to claim 15, characterized in that the substrate before forming the transparent or quasi-transparent layer arbitrarily formed three-dimensional, in particular is bent. A method according to claim 15 or 16, characterized in that the full-surface application by CVD or PVD method, in particular spray pyrolysis, sputtering or sol-gel technique is applied. Method according to one of claims 15 to 17, characterized in that connection points ( 9 ), comprising conductive paste or lacquer, are applied to the conductive layer and then baked, for connecting individual electrical or electronic components. A method according to claim 18, characterized in that individual components with a soldering process on the connection points ( 9 ) are applied and thus conductively connected to the conductive layer. A method according to claim 18 or 19, characterized in that the transparent substrate is biased during baking. Method according to one of claims 15 to 17, characterized in that anisotropic or isotropic conductive adhesive for the connection of individual electrical or electronic components is applied to the conductive layer.

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